Patent Document 1 discloses an air conditioner with a flow diverter. The flow diverter is disposed between an expansion valve and a heat exchanger with a plurality of heat transfer pipes in a refrigerant circuit of the air conditioner. This flow diverter allows diversion of the refrigerant flowing from the expansion valve and then sends the refrigerant to each of the heat transfer pipes of the heat exchanger. A plurality of branched pipes connected to each of the heat transfer pipes of the heat exchanger and an expansion valve-side pipe communicating with the expansion valve are connected to the flow diverter.
Specifically, the flow diverter has a flow diverter main body 101, a first connection portion 102 which is provided at one end of the flow diverter main body 101 and to which an expansion valve-side pipe 110 is connected, and a second connection portion 103 which is provided at the other end of the flow diverter main body 101 and to which are connected a plurality of branched pipes 112, 112 . . . connected to each of the heat transfer pipes of the heat exchanger, as shown in FIGS. 11A and 11B.
The first connection portion 102 is in the shape of a cylinder with open ends. The first connection portion 102 has the expansion valve-side pipe 110 inserted therein and is brazed to the expansion valve-side pipe 110. Each of the branched pipes 112 is connected to the second connection portion 103. The branched pipes 112 are provided side-by-side at intervals on the circumference 104 of a circle around a central axis c1 of the first connection portion 102.
In this flow diverter 100, the refrigerant flowing from the expansion valve flows from one end of the flow diverter main body 101 to the other end thereof. The refrigerant is then divided by flowing into the branched pipes 112 connected to the second connection portion 103. Here, in the second connection portion 103, the plurality of branched pipes 112, 112 . . . are provided side-by-side at intervals on the circumference 104 around the central axis c1 of the first connection portion 102. Therefore, by connecting the expansion valve-side pipe 110 to the first connection portion 102 in such a manner that the central axis of the expansion valve-side pipe 110 is in line with the central axis c1 of the first connection portion 102, the flow diverter 100 can uniformly divide the refrigerant from the expansion valve-side pipe 110 into the branched pipes 112. In other words, when the refrigerant flows from the expansion valve toward the heat exchanger in the refrigerant circuit, the refrigerant flows toward the second connection portion 103 into the flow diverter main body 101 in the direction of the central axis c1 of the first connection portion 102. Furthermore, in the flow diverter main body 101, the branched pipes 112 are equally distant from the expansion valve-side pipe 110. For this reason, the refrigerant can uniformly flow into the branched pipes 112 after passing through the flow diverter main body 101. As a result, the air conditioner with this flow diverter 100 can prevent the refrigerant from flowing non-uniformly into the heat transfer pipes of the heat exchanger at varying flow rates and inhibit deterioration of heat exchange efficiency of the refrigerant that can be caused by the varying flow rates thereof in the heat transfer pipes.
When connecting the expansion valve-side pipe 110 to the flow diverter 100 at the time of production of the air conditioner, the expansion valve-side pipe 110, the expansion valve-side pipe 110 is inserted into the first connection portion 102 of the flow diverter 100 and brazed to the first connection portion 102 in inserted condition. In so doing, sometimes the expansion valve-side pipe 110 is connected (brazed) to the flow diverter 100, with the central axis c2 of the expansion valve-side pipe 110 being inclined with respect to the central axis c1 of the first connection portion 102, as shown in FIG. 12. This happens because the inner diameter b1 of the inner peripheral surface of the first connection portion 102 is set so that the space for pouring (to be filled with) solder for brazing and for ensuring brazing strength is formed between this inner peripheral surface and the outer peripheral surface of the expansion valve-side pipe 110.
Connecting the expansion valve-side pipe 110 to the flow diverter 100 while the expansion valve-side pipe 110 is inclined as described above creates imbalance in the flow rate of the refrigerant flowing into the branched pipes 112 through the flow diverter 100. That is described hereinafter in more detail.
When the expansion valve-side pipe 110 is connected to the flow diverter 100 while inclined, the refrigerant flowing from the expansion valve toward the heat exchanger in the refrigerant circuit flows into the flow diverter 100 in a direction that is inclined with respect to the direction of the central axis c1 of the first connection portion 102. In addition, the branched pipes 112 that are disposed on the circumference 104 in the second connection portion 103 are apart from the expansion valve-side pipe 110 of the flow diverter 100 by varying distances. This causes imbalance in the flow rate of the refrigerant flowing into the branched pipes 112 through the flow diverter 100. This means that the flow diverter 100 cannot uniformly divide the refrigerant flowing from the expansion valve-side pipe 110 into the branched pipes 112.
In this case, the efficiency of exchanging heat between the refrigerant and outside air in the heat exchanger deteriorates due to the imbalance in the flow rate of the refrigerant in the heat transfer pipes of the heat exchanger.
Patent Document 1: Japanese Patent Application Publication No. 2003-35471